Nonwoven/film laminates

ABSTRACT

The invention relates to a method for producing nonwoven/film laminates for personal hygiene articles, from an initial film web consisting of a thermoplastic polymer and an initial nonwoven web. According to said method, the initial film web and the initial nonwoven web, whose melting point lies above the crystallite melting point of the polymer, are heated to a temperature that exceeds the crystallite melting point of the polymer and lies below the melting point of the initial nonwoven web. The laminate is then guided through a cooled nip and is cooled to a temperature that lies below the crystallite melting point of the initial film web. The invention also relates to laminates that can be produced by said method.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a Divisional of U.S. application Ser. No.11/574,535, filed Apr. 3, 2007, which is the National Stage ofInternational Application No. PCT/EP05/08903, filed Aug. 17, 2005, whichis based upon and claims the benefit of priority from prior GermanPatent Application No. 10 2004 042 405.5, filed Sep. 2, 2004, the entirecontents of all of which are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION

The invention relates to improved nonwoven-film laminates and to amethod for the production thereof.

Being a waterproof material and, if desired, a material that isbreathable at the same time, plastic films have become indispensable ina multitude of technical fields and daily life. An broad field ofapplication relates to personal hygiene articles, such as diapers.

While known films meet the requirements for tightness, lightness andbreathability to a satisfactory extent, their stability and, above all,their surface condition which is also referred to as “grip” fail to beoptimal. In particular, breathable films exhibit poor tear resistance,and the use of thicker and, thus, more stable films increases the costincurred. As regards the grip, the smooth glossy surface of plasticfilms is felt to be unpleasant. Particularly the internal surface ofpersonal hygiene articles, which is sitting directly on the skin, andthe external surface as well should be felt to be soft and, if possible,give a feeling similar to textile. Smooth films give the impression ofclinging to the skin, even if they are breathable films.

A further problem is the development of noise, also referred to as“rustling”, which is, in particular, caused by thin films in personalhygiene articles during movements of the wearer. Such rustling should beavoided as far as possible since, otherwise, the acceptance of thepersonal hygiene article would be impaired.

In order to overcome the above problems, innumerable suggestions havebeen made for a modification of the films as such and also for theapplication of laminates made of films containing woven or nonwovenfabrics.

For example, DE 195 38 049 describes a method for the production of afilm web which, on the one hand, exhibits improved transverse elasticityand puncture resistance and, on the other hand, improved softness andreduced rustling. Therein, an initial film web consisting of athermoplastic polymer is heated up to the molten state and above thecrystallite melting point of the polymer by means of one or more heatingcylinders and is subsequently guided through a cooled nip.

Wide-spread use is also made of laminates consisting of non-woven orwoven fabrics or films, since these combine the waterproofness of thefilm with the textile like surface of woven or nonwoven fabrics.Nonwoven fabrics are used primarily. In the most simple case, thelaminates consist of a film and a nonwoven fabric, which can be combinedwith each other in various manners. Thermobonding, adhesive bonding anddirect extrusion (cast method) are the most current methods.

In thermobonding, a stamping roller (=engraved steel roller) is used,mostly together with a smooth steel roller as a second roller, to fusethe material of the film and/or nonwoven fabric in a localized manner bymeans of high temperature and pressure, with the result that the twomaterial webs are bonded to each other. The method has the disadvantagethat, owing to the conditions prevailing during bonding, the film may bedamaged and may, therein, lose its liquid tightness, this also beingreferred to as pinholing. In addition, the bonds are only localized,this having an adverse effect on the composite strength.

U.S. Pat. No. 5,837,352 discloses an example, describing laminatesconsisting of a film and nonwoven fabric, which may be bonded throughthermobonding or ultrasonic or other methods.

Although with adhesive bonding there is achieved a bonding across theentire surface, it results in a deterioration of the breathability ofbreathable films. What is more, bonding agents cause additional cost andare, in part, suspected of being harmful to health. If, however,localized bonding instead of full-surface bonding is chosen in order topreserve breathability, the composite strength will suffer.

As an alternative to adhesive bonding, films and/or nonwoven layers maybe provided or additives may be introduced in the film and/or nonwoven,this allowing bonding at substantially lower temperatures, if thethermobonding method is used. U.S. Pat. No. 5,695,868 describes anexample, where a component referred to as bonding agent is contained ineither the film or the non-woven or even in both. This component allowsthermobonding below the melting point of the film and nonwoven, with theresult that the breathability of the film is preserved, and bondingremains localized.

Direct extrusion is a cost-effective method for non-breathablelaminates, ensuring a reliable compound strength, but causing poorsoftness and a high pinholing risk. If breathable laminates are desired,breathability can only be achieved in a second step through reworking ofthe composite. For this purpose, either fillers causing the formation ofpores thereon when the laminate is stretched are contained in the film,or the laminate is provided with pores through needling.

For example, U.S. Pat. No. 5,865,926 discloses a film which is extrudedon a nonwoven web and, subsequently, the composite is stretched(ring-rolled) by means of surface-textured rollers in order to make thecomposite breathable.

Finally, use is also made of methods where nonwoven fabrics are providedwith a coating, in order to achieve the desired tightness againstliquids with simultaneous permeability to water vapor. An examplethereof is described in U.S. Pat. No. 5,879,341.

SUMMARY OF PREFERRED EMBODIMENTS

None of the known methods is able to meet all requirements in an optimummanner. For that reason, there is a constant demand for improvedlaminates and improved methods for the production of laminates.

Surprisingly, it has now been found that laminates with excellentbreathability, softness and rustling values can be produced by heating afilm up to the molten state and combining said film with a nonwoven atthis temperature and by then guiding the composite through a cooled nip.

Thus, the aforementioned problems are solved by a method for theproduction of a laminate from an precursor film web and a precursornonwoven web, wherein the precursor film web consisting of athermoplastic polymer and the precursor nonwoven web whose melting pointis in excess of the crystallite melting point of the polymer are heatedup to a temperature above the crystallite melting point of the polymer,with the laminate then being guided through a cooled nip. Theaforementioned problems are also solved by laminates produced by saidmethod.

Surprisingly, the molten polymer of the film web adheres to thenon-molten nonwoven web. This composite is fixed in the subsequentcooled nip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the thermal lamination method accordingto the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The precursor film web is produced in known manner, e.g. by blowextrusion. In general, all thermoplastic polymers can be used asmaterials for the film. A multitude of commercial products is availableon the market. Preferrably, use is made of LDPE (low densitypolyethylene), LLDPE (linear low density polyethylene), MDPE (mediumdensity polyethylene), HDPE (high density polyethylene), and various PPs(polypropylene) as well as copolymer of ethylene or propylene with othercomonomers. These polymers are either used in their pure form or aspolymer mixtures. Usual formulations for hygiene films are, for example,mixtures of 10 to 90% by weight of LDPE, 10 to 90% by weight of LLDPEand 0 to 50% MDPE, such as a mixture of 80% LDPE, 20% LLDPE and pigmentsmeeting the particular requirements. Commercial polymers for hygienefilms have the melting ranges or crystallite melting points listedbelow:

-   LDPE=112 to 114° C.-   LLDPE=119 to 125° C.-   MDPE=125 to 128° C.

Usually, hygiene films are dyed, e.g. white with titanium dioxide. Inaddition, they are provided with usual additives and processing agents,some of which are the molder's trade secret.

Further suitable substances are ethylene vinyl acetate (EVA), ethyleneacrylate (EEA), ethylene ethyl acrylate (EEA), ethylene acrylic acid(EAA), ethylene methyl acrylate (EMA), ethylene butyl acrylate (EBA),polyester (PET), polyamide (PA), for example nylon, ethylene vinylalcohols (EVOH), polystyrene (PS), polyurethane (PU), and thermoplasticolefin elastomers.

Preferred materials for the precursor film web are polyolefins, such asLDPE, LLDPE and PP. Most preferred materials are mixtures of thesepolymers, such as mixtures of LDPE and LLDPE, mixtures of LDPE or LLDPEand PP, or mixtures of PE or PP with different melting points.

The precursor nonwoven web is also produced in known manner. Allnonwoven fabrics containing at least one formulation component based ona thermoplastic polymer are useful. The non-wovens may contain fibers ofPE, PP, PET, Rayon, cellulose, PA, and mixtures of these fibers. It isalso possible to use bicomponent or multicomponent fibers. Mostpreferred materials are, for example, nonwovens made of spun or staplefibers based on PP, PE or PET, as well as nonwovens made of mixtures ofPP and PE or mixtures of PET and PP or PE.

In general, the thermal lamination method according to the invention canbe utilized with all thermoplastic formulations, wherein the meltingpoints and raw materials must be coordinated with each other, as is thecase with the thermobonding method. In general, the webs to be laminatedmust comprise a similar morphology in at least one formulationcomponent, in order to achieve a reliable basis for adequate compositeadhesion through temperature.

The number of webs to be laminated is not limited; however, thenecessary heating of the webs, for example through a heating cylinder,must be ensured before said webs reach the cooled nip. It is not onlypossible to laminate nonwovens with films, but also any conceivablecombination (e.g. nonwoven-nonwoven; nonwoven-film-nonwoven; film-film;etc.).

The precursor webs may have been produced by any known method, but mustcontain thermoplastic components. Here, it is important to coordinatethe materials of film and nonwoven with each other, on the one hand bychoosing crystallite melting points which are sufficiently spaced apartfrom each other and, on the other hand, by choosing materials which aresufficiently compatible with each other to allow bonding. Theappropriate material combinations are known to those skilled in the artand can also be determined by means of a few orienting tests.

The difference in the crystallite melting point of the precursor filmweb or the low-melting component of the precursor film web should be atleast about 5° C., preferrably at least about 10° C., and mostpreferrably at least about 20° C. below the melting temperature of theprecursor nonwoven web or below the melting temperature of thehigh-melting component of the precursor nonwoven web.

To achieve a better compatibility, a low-melting component may becontained in the precursor film web or the precursor nonwoven web or inboth thereof. Herein, it must be ensured that at least one component ofthe precursor nonwoven web comprises a melting point above thecrystallite melting temperature of the precursor film web or of thelower-melting component in the precursor film web.

To improve material compatibility, it is also possible to use two-layeror multi-layer nonwovens where the layer in the laminate that is incontact with the precursor film web consists of a lower-melting materialor contains a lower-melting material than the further layer(s).

According to the invention, the precursor film web and the precursornonwoven web are jointly heated through a preferrably antistick-coatedheating cylinder and are then guided through a cooled nip. As a matterof course, it is also possible to use a plurality of heating cylindersor other heating methods, such as infrared radiators. For reasons ofclarity, however, the invention will be described below with regard toone heating cylinder only.

In a preferred embodiment, the precursor nonwoven web is in directcontact with the surface of the heating cylinder. The precursor film webis carried along on top thereof. The temperature of the heating cylinderis selected such that the precursor film web is heated up to the moltenstate across the wrap distance of the heating cylinder, however, suchthat this temperature does not yet initiate the molten state for thecarried-along precursor nonwoven web, i.e. this temperature must bebelow the crystallite melting point of the precursor nonwoven web.

Since the nonwoven web that is not in the molten state yet bears on theheating cylinder, it is ensured that the molten film web resting on topthereof can be detached in an easy manner that is highly stable withregard to the process.

It is, however, also possible to apply the method with the film webhaving direct contact to an antistick-coated heating cylinder and anonwoven web arranged on top thereof.

In the following cooled nip, the laminate is cooled to temperaturesbelow the crystallite melting point of the film web. Preferrably, thecooled nip consists of a steel roller and a counterpressure rubberroller. The steel roller is, preferrably, provided with a textile-typeengraving which further supports the textile appearance of the laminatesurface. The preferrably used embossed texture of the steel rollerreduces the degree of gloss of the laminate.

Contrary to known thermobonding lamination methods wherein two heatedsteel rollers (raised engraved roller and smooth counterpressure roller)are used to guide a film web and a nonwoven web and the composite iscreated through temperature and very high pressures in a localizedmanner only, the thermal lamination method according to the inventionprovides full-surface lamination. Similar to the known adhesivelamination methods, this is to advantage in that, owing to low pressuresin the lamination process (pressureless heating, lamination step in thecooled nip over the entire surface and with soft rubber roller ascounterpressure roller), very soft laminates (similar to adhesivelaminates) are created without use of adhesives and, on the other hand,the risk of material damage (perforations, pinholes) incurred withthermobonded laminates is excluded.

The composite adhesion between nonwoven and film can very easily becontrolled through the degree of heating. The higher the temperature ofthe surface of the heating cylinder, the higher the composite valuesbetween nonwoven and film. The heating process window at the minimumtemperature is provided through the absolutely necessary molten state ofthe raw material component responsible for composite adhesion.

The upper heating limit is provided through the crystallite meltingpoint of the nonwoven web. If heating goes beyond the crystallitemelting point of the nonwoven web, the resulting laminates will have anindestructible bond between the nonwoven web and the film web; however,the high softness of the laminate will be lost, causing the risk ofholes similar to the direct extrusion or thermobonding methods.

Contrary to the known adhesive lamination methods, the thermallamination method according to the invention is to advantage in that ahigh softness of the products is achieved without the use of anadhesive. Moreover, said method allows the production of trilaminates(nonwoven-film-nonwoven) without requiring major modifications to theplant. In this case, it is only necessary to carry along a secondnonwoven web over the two initial webs and to also heat said web througha heating cylinder or heating cylinders.

As compared with the classic thermobonding method, the thermallamination method is to advantage in that the produced laminates have ahigher softness and material damage caused by high pressures andtemperatures is avoided. As a result, these laminates are not associatedwith the risk of perforations or microholes (“pinholes”) which representa considerable defect in personal hygiene articles (leaky diapers), forexample when such laminates are used as backsheets.

As compared with laminates produced according to the known directextrusion method, the combined nonwoven-film laminates provide a highersoftness while the risk of defective spots (perforations, pinholes) isclearly reduced. With direct extrusion, the melt film is applied to thenonwoven directly downstream of the slot die and at extrusiontemperature. The nonwoven-film web composite is produced in a subsequentcooled nip. Owing to the necessary high extrusion temperatures (e.g.approx. 230° C. for LDPE-LLDPE-PP mixtures, corresponding to approx. 70°C. above the crystallite melting point of the highest-meltingformulation component), the molten film web has a very low viscositywhen it is applied to the nonwoven web. In combination with thesubsequent cooled pressure-controlled nip, the low-viscosity film webpenetrates the nonwoven web to a very high extent. As a result, thelaminate is hardened and the nonwoven filaments pierce the film web,this in turn being a cause of perforations and pinholes in the finishedproduct.

Contrary thereto, the invention allows highly precise adjustment of theviscosity of the molten film web by means of the heating cylinder. Bydecoupling the extrusion and lamination procedure, the high extrusiontemperatures can be restricted to this procedure and substantially lowertemperatures can be used for the lamination procedure. Contrary to thedirect extrusion method (with identical formulations), the invention,hence, allows lamination with the composite values usually required forpersonal hygiene articles (>0.10 N/cm) as early as when the crystallitemelting point of the raw material component in the film web responsiblefor the lamination behavior is reached.

As compared with direct extrusion lamination, the present invention isfurther to advantage in that the laminates produced according to theinvention can be printed. According to the invention, the film can beprinted after the extrusion procedure and before the laminationprocedure. This allows printing on the film side which will be coveredby the nonwoven in the future laminate. This results in an excellentprinting quality, because it is possible to print on the smooth filmweb. The nonwoven which, in the finished laminate, will be arrangeddirectly on top of said smooth film web affects the print image only toan inconsiderable degree, but will prevent abrasion of the printing inkin the finished product. If the laminates printed according to theinvention are, for example, used as backsheets for diapers, the surroundcannot become dirty through abrasion of the printing ink, since thelatter is covered by the nonwoven.

As regards breathable laminates, this embodiment is further to advantagein that the stretching step for creating the breathability infiller-containing films is, preferrably, also achieved before theprinting and lamination procedures. This prevents the print subjectsfrom being distorted while stretching is in progress.

With direct extrusion (the molten film web is bonded to the nonwoven webdirectly downstream of the slot die), it is not possible to print on thefilm web nor to cover same with the nonwoven web. With this method, itis either possible to print on the nonwoven side (=external surface ofthe various finished products (e.g. diapers)), this allowing only ahighly restricted printing quality and posing the danger of printing inkabrasion in the finished product. Or the side facing the film can beprinted before the film is applied, but then the printing quality willremain poor and printing on the nonwoven requires a great amount ofprinting ink. Further, direct extrusion laminates can be printed byprinting on the film side according to what is called the counter printmethod. Therein, the print subject is visible through the nonwoven andfilm layers in the finished product. In this case, the print subject canbe seen to a limited degree only or not at all; this is particularlyapplicable to strongly dyed opaque films (for example chalk-filledbreathable films).

As a matter of course, the method according to the invention canimmediately follow the production of the precursor film web, for exampleby extruding a film web through a slot system and cooling by means of astamping unit, a chill-roll system or even a cooling roller or coolingrollers only. Such a system is then equipped with one or more downstreamheating cylinders according to the invention with subsequent cooled nip.If desired, a printing unit is installed upstream of the heatingcylinder(s) according to the invention.

In a further preferred embodiment, the nonwoven-film combination is,after the lamination procedure, subjected to a ring-rolling step incrossways direction to the web. On the one hand, this stretching incrossways direction (CD) reduces the base weight of the laminate,broadens the web in crossways direction and increases the softness ofthe finished product. These described changes in property can be easilymanipulated through the geometry used and through the degree ofengagement of the ring-rolling rollers. As a matter of course, thelaminates can also be subjected to a ring-rolling step in machinedirection (MD) or in crossways and machine direction (CD+MD). Since thedepth of penetration of the film web into the nonwoven web can be easilycontrolled through the heating cylinder, the formation of perforationsand/or pinholes in the stretching procedure can be easily prevented.

FIG. 1 is a schematic diagram of the thermal lamination method accordingto the invention. A precursor nonwoven web 2 is guided over thedeflection roller 3 and a precursor film web 1 is guided over thedeflection and impression roller 4. Said webs 2 and 1 are both guidedonto a heating cylinder 5. There, the two webs are jointly heated to atemperature above the crystallite melting point of the precursor filmweb and below the crystallite melting point of the precursor nonwovenweb. Therein, the nonwoven web is bearing on the cylinder 5.Subsequently, the composite formed on the heating cylinder 5 is fixedand cooled in the stamping unit which consists of the stamping roller 6and the rubber roller 7. The composite is guided over the deflectionrollers 8 and 9 and is then subjected to a stretching step which isachieved in crossways direction through the ring-rolling rollers 10 and11. Thereafter, the finished laminate can be further processed in knownmanner.

The examples following below are intended to illustrate the invention,however without restricting it thereto.

EXAMPLE 1 Nonwoven-Film Laminate (Non-Breathable)

A precursor film web consisting of 30% polypropylene (melting pointranging from 137 to 143° C.), 60% LDPE and 10% LLDPE is blow-extruded in14 g/m². Thereafter, the precursor film web and a precursor nonwoven web(14 g/m²) based on polypropylene are jointly fed to a system, such as itis schematically represented in FIG. 1. The polypropylene of the filmweb differs from the polypropylene of the precursor nonwoven web in thatits DSC crystallite melting point is approx. 20° C. lower. The precursornonwoven web is in direct contact with the surface of the heatingcylinder. The precursor film web is carried along on top thereof. Thetemperature of the heating cylinder is selected such that, over the wrapdistance of the heating cylinder, the precursor film web is heated up tothe molten state at a temperature ranging from 137 to 143° C. At thistemperature, the carried-along precursor nonwoven web does not reach themolten state yet. In the subsequent cooled nip, the laminate is cooleddown to a value below the crystallite melting point of the film web.

The laminate showed composite values of >0.10 N/cm as required forpersonal hygiene articles.

EXAMPLE 2 Nonwoven-Film Laminate (Non-Breathable)

A precursor film web consisting of 70% LDPE (melting point ranging from108 to 113° C.) and 30% LLDPE (117 to 124° C.) is blow-extruded in 14g/m². Thereafter, the precursor film web and a precursor nonwoven web(14 g/m², melting point ranging from 131 to 135° C.) based onpolypropylene are jointly fed to a system, such as it is schematicallyrepresented in FIG. 1. The LDPE of the film web differs from thepolypropylene of the precursor nonwoven web in that its DSC crystallitemelting point is approx. 20° C. lower. The precursor nonwoven web is indirect contact with the surface of the heating cylinder. The precursorfilm web is carried along on top thereof. The temperature of the heatingcylinder is selected such that, over the wrap distance of the heatingcylinder, the precursor film web is heated up to the molten state at atemperature ranging from 114 to 125° C., either in part (above LDPEmelting point) or as a whole (above LDPE and LLDPE melting points). Atthis temperature, the carried-along precursor nonwoven web does notreach the molten state yet. In the subsequent cooled nip, the laminateis cooled down to a value below the crystallite melting point of thefilm web. To achieve an appropriate composite, the molten state of theLDPE formulation component is already sufficient.

The laminate showed composite values of >0.10 N/cm as required forpersonal hygiene articles.

EXAMPLE 3 Nonwoven-Film Laminate (Breathable)

A precursor film web (precursor film) is blow-extruded. The formulationof the film web consists of 70% polypropylene compound (melting pointranging from 137 to 143° C.) and 30% LLDPE compound (117 to 124° C.)wherein the compounds each consist of a mixture of raw material plus 60%CaCO₃ (chalk). Thereafter, the precursor film web and a precursornonwoven web (14 g/m²) based on polypropylene are jointly fed to asystem, such as it is schematically represented in FIG. 1. Thepolypropylene present in the film web differs from the polypropylene ofthe precursor nonwoven web in that its DSC crystallite melting point isapprox. 20° C. lower. The two webs are jointly heated through anantistick-coated heating cylinder and then guided through a cooled nip(stamping roller and a counterpressure rubber roller) The precursornonwoven web is in direct contact with the surface of the heatingcylinder. The precursor film web is carried along on top thereof. Thetemperature of the heating cylinder is selected such that, over the wrapdistance of the heating cylinder, the precursor film web is heated up tothe molten state at a temperature ranging from 137 to 143° C., but thatthe carried-along precursor nonwoven web does not reach the molten stateyet at this temperature. In the subsequent cooled nip, the laminate iscooled down to a value below the crystallite melting point of the filmweb.

In the present exemplary embodiment, the nonwoven-film combination is,after the lamination procedure, additionally subjected to a ring-rollingstep in crossways direction to the material web. This stretching step isintended to generate breathability. That means that fine pores areformed around the chalk grains (mean particle size ranging from 0.8 to3.0 μm) for achieving breathability, the maximum permissible size ofsaid pores being approx. 1 μm to preserve liquid tightness. Themeasurement as to ASTM E 398 (38° C., 90% relative air humidity,measuring instrument LYSSY L 80-5000 Lyssy AG, CH) resulted in apermeability to water vapor ranging from 2200 to 2500 g/m² in 24 h.

Depending on the size of the chalk grains used and the ring-rollingpenetration depth, a permeability to water vapor ranging from 500 to3500 g/m² in 24 h can be achieved.

EXAMPLE 4 Nonwoven-Film Laminate (Highly Breathable)

In a first step, a precursor film web (precursor film) is blow-extruded.The formulation of the film web consists of 70% low-meltingpolypropylene compound (melting point approx. at 130° C.) and 30%high-melting polypropylene compound (melting point ranging from 158 to164° C.). The compounds each consist of a mixture of raw material plus55% CaCO₃ (chalk).

After the so-called precursor film has been blow-extruded, the film isstretched in machine direction in a monoaxial MDO stretching unit.Therein, 100% of the film web is stretched in machine direction with thestretching degree ranging from 1:1.5 to 1:4.0, thus producingbreathability. Contrary to partial stretching in ring-rolling, MDOstretching allows to reach very high breathabilities without posing therisk of perforations or pinholes and, thus, of film webs that arepermeable to liquid; this is achieved by means of high stretchingdegrees and owing to the fact that the entire film web area is availablefor stretching.

After completion of the stretching step, the breathable film web can bevery easily printed if desired, using the usual methods. The smooth filmsurface provides the basis of highly precise print images on the filmweb, and the print subjects are preserved, showing no distortions causedby the previous stretching step. For example, breathable directextrusion laminates (nonwoven-film laminates) are not stretched beforeprinting on the nonwoven web and the lamination procedure are completed.Therein, the print subjects are distorted through this followingstretching step.

Subsequently, the breathable film web and a precursor nonwoven web (14g/m²) based on polypropylene are jointly heated through anantistick-coated heating cylinder and then guided through a cooled nip.The polypropylene present in the film web differs from the high-meltingpolypropylene of the precursor nonwoven web in that its DSC crystallitemelting point is approx. 20° C. lower. In two nonwoven layers, theformulation of the three-layer precursor nonwoven web consists of ahigh-melting polypropylene (crystallite melting point ranging fromapprox. 150 to 165° C.). Similar to the film web, the third nonwovenlayer (=external surface=lamination side facing the film) was made of apolypropylene having a melting point of approx. 130° C.

The precursor nonwoven web is in direct contact with the surface of theheating cylinder, wherein the nonwoven layer having the reduced meltingpoint faces the precursor film web. The precursor film web is carriedalong on top thereof. The temperature of the heating cylinder isselected such that, over the wrap distance of the heating cylinder, theprecursor film web is, in part, heated up to the molten state of thelow-melting PP compound, but such that this temperature (ranging from130 to 140° C.) does not cause the carried-along precursor nonwoven webto reach the molten state of the two high-melting PP nonwoven layersyet. Therein, the third low-melting PP nonwoven layer is heated up tothe crystallite melting point. This nonwoven layer is in direct contactwith the precursor film web and supports an appropriate composite (>0.10N/cm) through the molten state. In the subsequent cooled nip, thelaminate is cooled down to a value below the crystallite melting pointof all formulation components of the film and nonwoven webs. Apermeability to water vapor ranging from 2000 to 3500 g/m² in 24 h hasbeen measured.

As in example 2, it is also possible to manipulate the permeability towater vapor by means of the parameters of filler particle sizes andring-rolling penetration depth. Values ranging from 500 to 5000 g/m² arepossible.

Additional ring-rolling in crossways direction further increases thesoftness and the permeability to water vapor.

The invention claimed is:
 1. A method for the production ofnonwoven-film laminates useful as a backsheet for personal hygienearticles, the method comprising: a) providing a film web made of atleast one thermoplastic polymer; b) providing a nonwoven web, whereinthe nonwoven web has a melting point in excess of the crystallitemelting point of the thermoplastic polymer; c) jointly heating the filmweb and the nonwoven web to a temperature above the crystallite meltingpoint of the thermoplastic polymer and below the melting point of thenonwoven web, in order to heat the entire film web to at least a moltenstate of the thermoplastic polymer and form the nonwoven-film laminate;and d) guiding the nonwoven-film laminate through a cooled nip in orderto cool the nonwoven-film laminate below the crystallite melting pointof the film web, wherein the heating comprises heating the film web andthe nonwoven web with a heating cylinder and further heating the filmweb and the nonwoven web with another heating method so that the filmweb is heated to the molten state.
 2. The method according to claim 1,wherein the other heating method comprises heating with radiant heat. 3.The method according to claim 1, wherein the other heating methodcomprises heating with an infrared radiator.
 4. The method according toclaim 1, wherein the cooled nip is formed by a stamping roller and arubber roller, wherein the embossed texture of the stamping rollerreduces the degree of gloss of the laminate.
 5. The method according toclaim 1, wherein the cooled laminate is subjected to a stretching stepin machine direction or crossways direction or in machine direction andcrossways direction.
 6. The method according to claim 1, wherein thefilm web is blow-extruded.
 7. The method according to claim 1, whereinthe film web is printed following extrusion but prior to lamination. 8.The method according to claim 1, wherein the film web is stretched inmachine direction or crossways direction or in machine direction andcrossways direction.
 9. The method of claim 1, wherein the nonwoven webis in direct contact with the heating cylinder.
 10. The method accordingto claim 1, wherein the film web further comprises a filler material.11. The method according to claim 10, wherein the filler material ischalk.
 12. The method according to claim 1, wherein the film webcomprises a second thermoplastic polymer, wherein the secondthermoplastic polymer has a melting point in excess of the crystallinemelting point of the thermoplastic polymer.